1. Technical Field
The present invention relates to an aromatic polycarbonate resin composition comprising: a reinforcing agent and/or a filler excellent in melt stability and appearance, and a production method thereof. More specifically, the present invention relates to an aromatic polycarbonate resin composition comprising: a reinforcing agent and/or a filler with improved thermal-hydrolysis resistance, dispersibility of reinforcing agent and/or filler and flame retardancy in addition to the above-described properties, and a production method thereof.
2. Prior Art
An aromatic polycarbonate is a resin material having excellent mechanical properties such as impact resistance and excellent heat resistance; thus, an aromatic polycarbonate is widely utilized as a housing material for various products such as computers, notebook-type personal computers, printers, word processors, copying machines, and the inner part material of electronic/electric equipment or a material for vehicle. To enhance rigidity, to prevent deformation caused by external stress, or to furnish dimensional accuracy to an aromatic polycarbonate, a method of formulating a reinforcing agent and/or a filler such as glass fiber, glass flake, carbon fiber or talc to a polycarbonate is often employed.
Such a method of formulating a reinforcing agent and/or a filler to an aromatic polycarbonate resin is disclosed in, for example, JP-A-5-302025, JP-A-5-222283, JP-A-6-256632, JP-A-6-207089, JP-A-6-287427, JP-A-9-3313, JP-A-9-157509, JP-A-9-316316, JP-A-2000-186194, JP-A-2000-327900 and JP-A-2001-19756.
However, an aromatic polycarbonate resin composition, comprising: a reinforcing agent and/or a filler, has a problem that decomposition of a base resin, an aromatic polycarbonate, is promoted due to the reinforcing agent and/or filler during molding processing. In particular, when a basic inorganic compound type filler such as talc and mica is used, the melt stability of an aromatic polycarbonate decreases significantly during melt kneading or molding processing, which results in a problem of significant deterioration of physical properties of the material. Furthermore, an aromatic polycarbonate resin composition comprising a reinforcing agent and/or a filler has a disadvantage of bringing about troubles such as silver streaks during injection molding to obtain a molded article, which impairs the surface appearance of the molded article.
Methods of improving melt stability of an aromatic polycarbonate resin composition comprising a reinforcing agent and/or a filler have been so far proposed as follows. That is, there has been: a method for combined use of an organic acid disclosed in JP-A-3-21664; a method for combined use of a phosphorous compound disclosed in JP-A-2-283760; and a method for combined use of a phosphonium sulfonate compound disclosed in JP-A-10-60248. A certain degree of improvement of the melt stability can be attained by these methods, however, the melt stability at high temperatures and/or for a longer period is insufficient, and the aromatic polycarbonate resin obtained by above methods still has a problem of insufficient melt stability in the case of molding at high processing temperatures. It is often necessary to elevate a melt resin temperature in order to decrease melt viscosity in a case where a molded article with a thin wall thickness is desired. Furthermore, the above prior technologies still have a problem of silver streaks generation, which impairs the surface appearance of the molded article.